Lubricating mechanism for sewing-machine loop takers



May 18, 1948. N ss 2,441,942

LUBRIGATING MECHANISM FOR SEWING MACHINE LOOP-TAKERS Filed May 17, 1945 H&

I William 7/402 Jlgs Patented May 18, 1948 LUBRICATIN G MECHANISM FOR SEWING- MACHINE LOOPTAKERS William C. Van Ness, Lynbrook, N. Y., assignor to The Singer Manufacturing Company, Elizabeth, N. J .a corporation of New Jersey Application May 17, 1945, Serial No. 594,347

7 Claims.

loop-taker, regardless of substantial variations in the levels of the lubricant supply.

More specifically, it is an object of the invention to provide a lubricant circulating system for maintaining .delivery to the loop-maker raceway of an adjustably regulated quantity of lubricant under conditions in which a minimum of lubricant need be drawn from a source of supply.

With these and other objects in View, as will hereinafter appear, the invention consists in the devices, combinations and arrangements of parts hereinafter described in connection with the accompanying drawings, which illustrate a preferred embodiment .of the invention and in which:

Fig. :1 represents a vertical longitudinal sec- ;tion of a portion of the bed-plate of a sewing machine containing the present improvement. Fig. 2 represents a yertical section of the loop- .ta-ker shaft and its bushing; the section .being taken-substantially on the line 2- 2 of Fig. 1. Fig. ;3 represents a longitudinal section of the loop-taker shaft mechanism; the section being taken substantially on .the line 3--3 of Fig. 2 and the loop-takerbeing shown as partly broken ,away. Fig. 4 represents a section similar to Fig.2,

buttaken.substantially on the line 4-4 of Fig. 1. V

Fig. 5 is an end elevationof the innerend of the loop-taker shaftbushing and pinion. I

The sewing machine in part illustrated in the drawings has a work-supporting bed-plate HI provided with a throat-plate H havinga needleaperture 32. The bed plate It has depending wallsformed to provide .a gear-casing and a main oil-reservoir chamber 53 having a bottom closure-plate l4 suitably secured to said walls.

'Secured'by a screw IS in a wall E5 of the gearcasing, is a bushing Iiin which is journaled a horizontally disposed rotary actuating shaft iii. The shaft l8 may be rotated by any suitable driving connections therewith. Secured to the end of the shaft 18 within the oil-reservoircha-mber l3 is -the hub of an internal driving gear l9.

In mesh with the teeth of the internal gear i9 is a pinion '2!) having its horizontal axis of rotation preferablylying in a vertical plane containing the axis of rotation of the driving shaft 18. The ratio of the internal-gear l9 and pinion 20 is such that said pinion rotatestwice for each .gear 19 with the pinion 20.

rotation of the gear l9. The pinion 2B, which is also disposed in theoil-reservoir chamber i3, is carried by one end of a horizontally disposed looptaker shaft '21 and is preferably integral with said shaft. Secured byscrews, as 22, upon the opposite end of the shaft 2| is the hub 23 of a rotaryhook form of loop-taker 24. The loop-taker 24 has the-usual cup-shaped body which is provided in its cylindrical side wall with a raceway 25 for the peripheral bearing-rib 26 of a threadcarrier 21 journaled in the loop-taker; said thread-carrier 21 being restrained, in any usual or suitable manner, against rotation with the loop-taker. The loop-taker shaft aperture in the hub 23 of the loop-taker is closed by a disk '28 set into the bottom wall 29 of the loop-taker;

the loop-taker being, as usual, mounted upon the shaft 2! so that the end of said shaft is spaced from the disk, whereby an oil-collecting recess 30 is provided in the loop-taker. Connecting the oilcollecting recess 30 and the raceway 25 is an angular lubricant-duct 3| provided in the body of the loop-taker.

The loop-taker shaft 2| is rotatably journaled in two horizontally spaced bearing-sleeves 32 and 33, which sleeves are suitably secured in the longitudinal opening 34 of a bushing 35. The

sleeve 32 forms a bearing for the shaft 2| adjacent the loop-taker 24 and the sleeve 33 forms a bearing for said shaft adjacent the pinion 20; the spacing of said sleeves providing a lubricantcollecting cavity in the bushing-opening 34 between the sleeves. The bushing35 is secured in a horizontal opening, provided in the wall 36 of the gear-casing, by a screw 31 which enters a groove 38 formed in the outer face of the bushing toextend lengthwise thereof. The described construction provides for assembly of the looptaker shaft 21 and its bearing-sleeves 32, 33 in the bushing 35 as a unit construction, as-well as for axial adjustment of the loop-taker 24 by endwise adjustment of the bushing 35 in the frame-wall 36.

One end portion of the bushing 35, extending into the oil-reservoir I3, is partly cut away to forma segmental extension 35 which partly surrounds the pinion '20 and affords the necessaryclearance for engagement of the driving- Secured by screws 39 in the bushing-extension 35 is a segmental block 40 which serves to hold the loop-taker shaft 2! against endwise movement in its bearings; a washer 4| being preferably interposed between the pinion 26 and the bearing-sleeve '33.

The bushing 35 is provided in its upper face with an oil-collecting cavity 42 which, in part,

is disposed in the oil-reservoir chamber I3; .said

cavity comp-rising an auxiliary lubricant-reserofthe inclined bottom wall of the oil-collecting cavity 42 is an upwardly enlarged reservoir outlet oil-duct 43 provided in the bushing'35 and disposed in vertical alinement with an inlet oil- The shaft-bearing face of the sleeve 33 is, of

course, directly lubricated by the oil supplied through the sleeve oil-duct 44 and also, in part,

by the oil discharged through the radial shaftaperture In order to insure adequate lubrication ofthe shaft-bearing face of the sleeve 32,

- said sleeve is provided in its inner face with a duct 44 provided radially in the bearing-sleeve 33. g V

The loop-taker shaft 2| is exteriorly provided,

in the portion of the shaft withinthe sleeve 33,:

with a spiral groove 45 which terminates atone from the sleeve-duct 44 to the inlet shaft-aperture 46 upon operation of the machine. Furthermore, the pitch of the spiral groove 45 is preferably sufficiently steep to insure that oil is forced into the shaft-aperture 46 under a pressure which is greater than the centrifugal force action which would oppose entrance of oil into the shaft-aperture 46. The shaft 2| has a longitudinal bore 41 extending from the loop-taker end of the shaft to a point adjacent the pinion 26, and the shaft-aperture 46 communicates with the shaft-bore 41 intermediate the ends of said bore. It will therefore be understood that during the operation of the machine, oil is not only fed or pumped under pressure into the shaft bore 41, but oil pressure is also built up in said shaft bore.

Threaded into the loop-taker end of the shaft 2! is a hollow cartridge 48 having its head end provided with a screw-driver slot. The cartridge 48 is internally threaded to retain therein one end of an oil-filtering wick 49 which extends a substantial distance into the shaft-bore 41. At the head end of the cartridge, the internally threaded portion thereof terminates in an axial cartridge-aperture 50 of reduced size and which is open to the oil-collecting recess of the looptaker.

Adjacent the inner end of the shaft-bore 41 and at the side of the sleeve oil-duct 44 opposite the radial shaft-aperture 46, the shaft 2! is radially provided with an outlet shaft-aperture 5| which connects the shaft-bore 41 with an annular groove 52 provided internally of the bearingsleeve 33. As illustrated in Figs. 2 and 3 of the drawings, the bearing-sleeve 33 is radially provided with a discharge or outlet duct 53 extending at an upward inclination from the sleevegroove 52. The bushing is also radially provided with an angular discharge duct 54 communicating with the duct 53 of the bearingsleeve; said duct 54 terminating in the auxiliary reservoir 42 and forming a lubricant-inlet duct of the reservoir. The shaft-aperture 5i, sleevegroove 52 and communicating outlet ducts 53 and 54 together comprise a pressure-relief port for the oil pumped into the shaft-bore 41 by the spiral groove 45 of the shaft.

In order to provide means for regulating the effectiveness'of the described pressure-relief port, the bushing 35 is longitudinally provided with a stepped bore 55 having a reduced portion 55' thereof intersecting the bushing-duct 54. Threaded into the bushing-bore 55, for endwise adjustment, is a shouldered valve-rod 56 disposed substantially parallel to the loop-taker shaft 21 and having its inner end conically shaped to provide a needle-valve 56. By endwise adjustment of the valve-rod 56, the position of the needle valve 56' may be regulated to vary the size of the pressure-relief duct, or completely to close said duct.

; even when the level of the supply groove 51 extending lengthwise of the sleeve. Ly-

ing in the groove 51 is one end portion of a wick '58,- of which the other end extends into contact with'the'inne r bottom face of the bushing 35 in thebushing-opening 34 between the sleeves 32 and 33. Some excess oil fed by the spiral groove 45 'will be discharged into the bushing-opening 34 between the bearing-sleeves 32, 33. In this manner, oil is supplied to the wick 58 and is fed thereby to the bearing-face of the sleeve 32. The portion of the shaft 21 within the sleeve 32 is exteriorly formed with a spiral groove 59 having a lead such as to feed excess oil back into the bushing-opening 34 between the bearing-sleeves.

The quantity of oil which may collect in the bushing-opening 34 is limited by the provision in the bushing 35 of a drain-aperture 66 having its inlet end disposed slightly above the level of the lowest portion of the opening 34. The aperture 66 is connected with the external bushin groove 38, ofwhich one end extends into the oil-reservoirchamber l 3.

In order more quickly to create a pressure of lubricant in the shaft bore 41, it is preferred to restrict the diametra-l size of the bore, between the wick 49 and the inner end of said bore, by inserting therein a rod 6|. Obviously, this may also be accomplished by correspondingly forming the shaft-bore. a

From the foregoing description, it will be understood that, during the operation of the machine, oil is continuously pumped under pressure into the loop-taker shaft bore 41 and that the oil is pressure-fed through the oil-filtering wick 49 and through the restricted cartridgeaperture 50 into the loop-taker recess 30, from which recess the oil is delivered through the lubricant-duct 3i to the raceway 25 of the looptaker. By endwise adjustment of the valve-rod 56, thepressure of the oil within theloop-taker shaft bore 41 may be regulated to a nicety to meet the requirements of different operating speeds and different kinds of work. To provide for access to the head end of the valve-rod 56, it is simply necessary to withdraw the thread-case 62 from its carrier 21 which is journaled in the loop-taker; the usual construction of the bottom walls of the thread-case carrier 21 land of the loop-taker 24 being such as to permit of use of a screw-driver for adjusting the valve-rod. The present construction, therefore, provides for adjustment of the oil-pressure in the shaft-bore without removal of the loop-taker from the shaft 21.

The quantity of oil supplied to the loop-taker raceway 25 is usually small in comparison with the quantity of oil bled from the shaft-bore 41 through the pressure-relief conduit. By returning the oil through the pressure-relief conduit to the auxiliary reservoir 42, there is thus provided a lubricant-circulating system requiring a minimum of additional oil to maintain constant the quantity of oil delivered to the'loop-taker raceway. This minimum quantity of, additional oil will b supplied from the main reservoir l3, of oil in the main reservoiris very low.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine, a rotary shaft having a longitudinal bore and having radial inlet and outlet apertures in the wall thereof, a loop-taker carried by said shaft and having a thread-carrier raceway, lubricant-conducting means connecting the bore of said shaft and said raceway, a lubricant-reservoir disposed above the level of said shaft, means effective upon rotation of said shaft for supplying lubricant under pressure from said reservoir through aid inlet aperture and into said bore of the shaft, a pressure-relief duct leading from the outlet aperture and con nected with said reservoir for re-circulation of said lubricant, and means for regulating the flow of lubricant through said pressure-relief duct.

2. In a sewing machine, a rotary shaft having a longitudinal bore and having radial inlet and outlet apertures in the wall thereof, a loop-taker carried by said shaft and having a thread-carrier raceway, lubricant-conducting means connecting the bore of said shaft and said raceway, a main lubricant-supply reservoir, an auxiliary lubricant-reservoir connected with the bore of said shaft, means for delivering lubricant from said main reservoir to said auxiliary reservoir, pump means effective upon rotation of said shaft for supplying lubricant under pressure from said auxiliary reservoir through said inlet aperture and into said bore of the shaft, a pressurerelief duct leading from the outlet aperture and terminating in said auxiliary reservoir, and means for regulating the flow of lubricant through said pressure-relief duct.

3. In a sewing machine, a rotary shaft provided with a longitudinal bore and having radial inlet and outlet apertures in the wall thereof; a loop-taker carried by said shaft and having a thread-carrier raceway; lubricant conducting means connecting the bore of said shaft and said raceway; a main lubricant reservoir; an auxiliary lubricant reservoir disposed above the level of said shaft; a lubricant circulating system for draining lubricant from said auxiliary reservoir, for pumping lubricant into said bore, and for discharging lubricant out of said bore and through said outlet aperture into said auxiliary reservoir; means for regulating the flow of lubricant in said circulating system; and means effective during the operation of said machine for supplying additional lubricant to said auxiliary reservoir.

4. In a sewing machine, a rotary shaft provided with a longitudinal bore and having radial inlet and outlet apertures, a loop-taker carried by said shaft and having means for receiving lubricant from said bore, a main lubricant reservoir, an auxiliary lubricant reservoir, means for supplying lubricant from said main reservoir to said auxiliary reservoir, and a lubricant circulating system for draining lubricant from said auxiliary reservoir, pumping it through said inlet aperture into said bore, and discharging it throughsaid outlet aperture and back into said auxiliary reservoir.

5. In a sewing machine, in combination, a frame affording a main oil reservoir; a drive shaft iournaled in said frame; a bushing secured in said frame and provided with oil-inlet and oiloutlet apertures, and with an auxiliary oil reservoir located above said main reservoir; a sleeve secured in said bushing and provided with oilinlet and oil-outlet apertures communicating with the corresponding apertures of said bushing; a

loop-taker shaft rotatably journaled in said sleeve and provided with a longitudinal bore and with radial oil-inlet and oil-outlet apertures communicating with the corresponding apertures of said sleeve; a loop-taker carried by one end of said shaft and provided with a thread-carrier raceway having oil-conducting connections with the bore of said loop-taker shaft; means including a member secured on said drive shaft for conveying oil from said main reservoir to said auxiliary reservoir; a completely organized oilcirculating system embodied in said bushing for transmitting oil from said auxiliary reservoir through said oil-inlet apertures, through the bore in said loop-taker shaft, through said oil-outlet apertures and back to said auxiliary reservoir; and valve means embodied in said system to maintain a back-pressure in the bore of said loop-taker shaft to force oil to said raceway in said loop-taker.

6. In a sewing machine having a frame provided with a horizontally disposed opening, a rotary shaft journaled in said frame, and a driving gear secured upon one end of said shaft; a loop-taker unit removably secured in said opening and comprising a bushing fitted in said opening, a rotary loop-taker shaft journaled in said bushing and provided with an axial bore, a looptaker carried by one end of said loop-taker shaft and provided with a thread-carrier raceway, a driven gear on the opposite end of said loop-taker shaft adapted to engage said driving gear when said loop-taker unit is inserted into said opening in the frame, lubricant-conducting means connecting said bore with said raceway, a lubricant reservoir formed in said bushin above said loop-taker shaft, and a lubricant circulating system carried wholly by said bushing for forcing oil from said reservoir into the bore in said looptaker shaft and from said bore back into said reservoir.

7. In a sewing machine having a frame provided with a horizontally disposed opening, a rotary shaft journaled in said frame, and a driving gear secured upon one end of said shaft; a loop-taker unit removably secured in said opening and comprising a bushing fitted in said opening, a rotary loop-taker shaft journaled in said bushing and provided with an axial bore, a looptaker carried by one end of said loop-taker shaft and provided with a thread-carrier raceway, a driven gear on the opposite end of said looptaker shaft adapted to engage said driving gear when said loop-taker unit is inserted into said opening in the frame, lubricant-conducting means connecting said bore with said raceway, a lubricant reservoir formed in said bushing above said loop-taker shaft, a lubricant circulat- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,230,461 Brush June 19, 1917 2,283,869 Graesser May 19, 1942 2,300,388 Parry Oct. 27, 1942 

